Rims & wear.

[FINNEY1973]

At what point does a rim become scrap. I've got a pair of MA3's on a bike i've traded and the wear looks to be fairly bad - concave to the eye and the ruler test, but what constitutes beyond safe to use?

What are people's general expectation in miles from a rim? I've just checked a few other pairs and found that my 50mm deep carbon rims (alu braking strip) also seem to be showing signs of wear (3,400 miles on these wheels) but nowhere near as bad as the MA3's.

 

[TGR]

I had to check the date on you post as there was an identical one a while ago. Someone was able to produce a pic of a rim which had been sawn in half - it was amazing/frightening to see how little metal was left in the rim walls.

Perhaps, the poster will see this and advise of mileage etc.

Richard

 

[FINNEY1973]

Was it this thread Richard? viewtopic.php?f=1&t=236662&start=0

I read that but it was MTB related so ignored it as such as MTB rims (I had assumed) would be much more robust and thicker walled to start with.

You're right though, a scary prospect and not one i'm going to risk but I'd like some guidance as to where the cut-off point is and a rim becomes scrap.

 

[TGR]

Nope, pretty sure it was road - perhaps a Mavic MA 2. I would not normally venture on the dark side!

Richard

 

[mattr]

I read that but it was MTB related so ignored it as such as MTB rims (I had assumed) would be much more robust and thicker walled to start with.

nope, not really.

Easy way to check is to find the original spec width of a new rim. Then see where it is now. Rim walls are generally less than 2mm thick. (And if you can find the original width, you may be able to find the rim wall thickness anyway. )

 

[FINNEY1973]

datasheet on 'freespoke' has MA3 inner & outer values so if correct 2.75mm would be the wall thickness. Whether that is correct I don't know but i'll have a look at mine to confirm they are for the skip

Just wondering if there was a cut-off point where you say that's it - they're done.

 

[TGR]

From memory (which is poor) I think the previous advice was measuring the depth and then deciding. What the 'safe measurement' was, i have no idea.

If you are throwing them out, run a hacksaw through the rim to see what was left. Obviously pics please!

Richard

 

[torqueless]

Might be something in this thread: http://www.retrobike.co.uk/forum/viewto ... c+module+e

Those rims are still going strong, anyway. When they fail, If I live to tell the tale, I'm seriously considering going back to wood sprints- (not that I was ever there before). At least with them you know how thick your sidewalls are..

 

[TGR]

I think that is the one i was thinking about, thanks (yet again) Torqueless.

Richard

 

[torqueless]

Jesus that was quick TGR! I didn't even get a chance to obsessively edit a pair of parentheses into my post.. (If you edit before someone else posts, it doesn't get to say: "edited by ......" at the bottom of your post).



Disclaimer: I cannot vouch for the dimensional accuracy of the cross-section drawings in that thread- more an artist's impression than a technical drawing..